Prepolymeric (meth)acrylates with polycyclic or aromatic segments

ABSTRACT

The invention relates to monomers according to the formulae: 
                 
 
as well as curable materials containing these monomers.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/EP01/06100 which has an Internationalfiling date of May 29, 2001, which designated the United States ofAmerica.

The invention relates to multifunctional (meth)acrylates with polycyclicor aromatic segments as well as materials prepared from them, inparticular dental materials.

The aesthetic aspect in restorative dentistry is becoming increasinglyimportant. In the anterior tooth area in particular, the patient can nolonger be expected to receive a restoration which does not correspond tothe natural tooth. The key to the aesthetic aspect is the opacity of therestoration material.

By restoration materials is meant within the meaning of this applicationin particular tooth filling materials, stump build-up materials, dentalcements, dental varnishes as well as dental materials, such as veneeringmaterials.

Dental restoration materials are based on curable monomers or monomermixtures. Predominantly used in the state of the art are short-chainedmonomers based on (meth)acrylates, which lead to a not inconsiderablehealth risk through the release of non-polymerized residual monomersfrom the restoration material. There has therefore been no lack ofattempts to switch to other monomer systems.

Thus for example the application DE-198 60 364 describes curablemonomers based on cyclic siloxane (meth)acrylates. These arecharacterized by a high (meth)acrylate functionality which, in the caseof curable materials prepared from same, leads to good physicalproperties.

Within the framework of the application DE-198 60 361, cyclicsol-gel-condensable siloxanes are described which, in curable materialsprepared from same, lead to a low polymerization shrinkage and improvedphysical properties.

Overall, in the state of the art there is no lack of polymerizablematerials which are characterized by low shrinkage and improved physicalvalues; however, there is indeed a lack of curable materials which haveimproved aesthetic properties, in particular an opacity which guaranteesthe visual impression of natural tooth substance.

The object of the present application is to provide monomers with highmolecular weight that allow the formulation of dental materials which inthe cured state have a low opacity in order to guarantee the visualimpression of natural tooth substance.

This object is achieved by the monomers according to the invention andthe materials formulated from same, according to the claims.

An advantage of the monomers according to the invention, in addition tothe fact that they have a high molecular weight, for example over 600g/mol, preferably over 800 g/mol, is also a high (meth)acrylatefunctionality, for example over 2, preferably over 3 in the case ofsurprisingly low viscosity. They are therefore extremely well suited forthe formulation of easily applicable materials.

The molecular weight of the monomers according to the invention can beso high until the limit of flowability is reached at 23° C.

The materials formulated from the monomers have a low polymerizationshrinkage and very high mechanical strength. It is therefore alsopossible to formulate materials without using customary low-functionalmonomers based on pure (meth)acrylate, which for example reduces therisk to the patient caused by emerging residual monomers.

The materials formulated from the monomers have in particular an opacityof 80 to 90%, preferably 83 to 87%.

Furthermore, it is advantageous and surprising that the monomers arestorage-stable despite their high number of acrylate or methacrylategroups per molecule.

The monomers according to the invention have the general formulae (1) or(2), the covalent bonding of a radical E to a siloxane backbone beingcommon to the formulae:

in which the following mean:

-   n=an integer from 0 to 10, preferably 1 to 5;-   A=H or linear or branched C₁ to C₁₅ alk(en)yl, preferably methyl,    ethyl, propyl, butyl, vinyl, ethinyl, allyl, or C₃ to C₁₅    cycloalk(en)yl, preferably cyclopentyl, cyclohexyl,    cyclopentadienyl, cyclohexenyl, or C₆ to C₁₂ aryl, preferably    phenyl, tolyl, xylyl, or C₈-C₁₈ alkaryl, preferably phenylethylenyl,    of the named radicals, one or more C atoms in each case being able    to be replaced by O, C═O, O(C═O), SiR₂ and/or NR, R being an    aliphatic radical with 1 to 7 C atoms, in which one or more C atoms    can be replaced by O, C═O and/or O(C═O);-   D=E or a hydrocarbon structure which links 2 to 10, preferably 2 to    5 cyclosiloxane radicals, the structure being linear or branched or    cyclic or polycyclic and containing 2 to 50, preferably 2 to 30 C    atoms and additionally 0 to 30, preferably 0 to 20 other atoms from    the group O, N, S, P, Cl, F, Br, I and to which 1 to 9, preferably 1    to 4 of the above-defined cyclosiloxane radicals according to    formula (1), excluding D, are attached. Preferred radicals D are:    di(prop-3-yl)ether, di(prop-3-yl)sulphide, di(prop-3-yl)amine,    di(prop-3-yl)methylamine, tri(prop-3-yl)amine, di(prop-3-yl)urea,    di(prop-3-yl)carbonate, ethylene glycol di(prop-3-yl)carbonate,    diethylene glycol di(prop-3-yl)carbonate, ethylene glycol    di(prop-3-yl)ether, diethylene glycol di(prop-3-yl)ether,    1,2-propanediol di(prop-3-yl)ether, 1,3-propanediol    di(prop-3-yl)ether, 1,3-butanediol di(prop-3-yl)ether,    1,4-butanediol di(prop-3-yl)ether, 1,4-butenediol    di(prop-3-yl)ether, 1,4-butinediol di(prop-3-yl)ether,    1,5-pentanediol di(prop-3-yl)ether, 1,6-hexanediol    di(prop-3-yl)ether, 1,8-octanediol di(prop-3-yl)ether,    1,9-nonanediol di(prop-3-yl)ether, 1,10-decanediol    di(prop-3-yl)ether, 1,12-dodecanediol di(prop-3-yl)ether, oxalic    acid di(prop-3-yl)ester, malonic acid di(prop-3-yl)ester, succinic    acid di(prop-3-yl)ester, adipinic acid di(prop-3-yl)ether, sebacic    acid di(prop-3-yl)ether, 1,2-ethanediyl, 1,4-pentadienyl,    1,5-pentanediyl, 1,5-hexadienyl, 1,6-heptadienyl, 1,7-octadienyl,    1,8-nonadienyl, 1,9-decadienyl, 1,11-dodecadienyl,    p-di(eth-2-yl)benzene, bis-(4-(prop-3-yl)oxyphenyl)-sulphone,    bis-(4-(prop-3-yl)oxyphenyl)-ketone,    bis-(4-(prop-3-yl)oxyphenyl)-methane,    1,1-bis-(4-(prop-3-yl)oxyphenyl)-ethane,    2,2-bis-(4-(prop-3-yl)oxyphenyl)-propane,    2,2-bis-(4-(prop-3-yl)oxyphenyl)-perfluoropropane,    2,2-bis-(4-(prop-3-yl)oxy-3,5-dibromophenyl)-propane,    3,3-bis-(4-(prop-3-yl)oxyphenyl)-pentane,    4,4-bis-(4-(prop-3-yl)oxyphenyl)-heptane,    1,1-bis-(4-(prop-3-yl)oxyphenyl)-cyclopentane,    1,1-bis-(4-(prop-3-yl)oxyphenyl)-cyclohexane,    1,1-bis-(4-(prop-3-yl)oxyphenyl)-3,3,5-trimethyl-cyclohexane,    1,1,1-tris-(4-(prop-3-yl)oxyphenyl)-ethane,    bis-((prop-3-yl-ether)oxy)-tricyclo[5.2.1.0^(2,6)]-decane;-   E=A or a polymerizable group taken from the group    G-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L and optionally also X-T-L, up    to 50%, preferably under 25% to 0% being permitted to correspond to    the groups E in an average molecule A, with the proviso that in the    case of molecules with only one siloxane ring, under 25% to 0% is    permitted to correspond to the groups E in an average molecule A,    and with the proviso that at least one group    G-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L must be contained in the    molecule;-   G=linear, branched or cyclic C₁ to C₂₅, preferably C₁ to C₂₀    alk(en)ylene, arylene, alkarylene, arylalkylene, 0 to 5 C atoms    being able to be replaced by a representative of the group O, S,    N-A, C(O), C(O)O, OC(O), C(O)N, NC(O), OC(O)O, NC(O)O, OC(O)N,    NC(O)N;-   X=C₁ to C₁₀ alk(en)ylene, preferably ethylene, methylethylene,    propylene, butylene, hexylene, ethenylene, propenylene;-   Q=a radical containing an aromatic or polycyclic ring system in the    chain, with 5 to 20, preferably 6 to 15 C atoms, which independently    of each other also has 0 to 5 heteroatoms from the group O, N-A, S    in the ring system;-   T=O, N-A or a bi- or multivalent linear, branched or cyclic alcohol,    amine or amino alcohol radical with 2 to 10 C atoms, preferably    ethanediol diyl, 1,4,7-trioxaheptane-diyl,    1,4,7,10-tetraoxadecane-diyl, 1,4,7,10,13-pentaoxatridecane-diyl,    glycerol-triyl, trimethylolpropane-triyl, pentaerythritol-tetryl;-   L=an acrylate or methacrylate group;-   a=2, 3.    in which the following mean:

x≦2+y+2z;

y=0, 1, 2, 3, 4, 5, 6, 7, 8, preferably 0, 1, 2, 3;

z=0, 1, 2, 3, 4, 5, 6, 7, 8, preferably 0, 1, 2, 3;

A and D have the above meaning with the proviso that at least 3 of theradicals D in a molecule must have the meaning ofG-C[(Q-T-L)_(a)(A)_(3-a)] or Q-L or X-T-L, and with the proviso thatwhere y=z=0, at least 1 radical D has the meaningG-C[(Q-T-L)_(a)(A)_(3-a)];

and the “*” symbols in (2.1) signify the connection points for fragments(2.2) via their valency symbolized by a “*” to the fragment (2.1).

Each selection of a radical named several times in the context of thisapplication via indices or via the multiple naming of the symbol is tobe considered independently of every other selection from the samegroup. For example, the triple naming of a radical A in a molecule canmean that the position A can be replaced by methyl and ethyl and propylin the same molecule.

Compounds according to formula (1) are based on cyclic siloxanes, one ormore siloxane rings being able to occur per molecule.

Compounds according to formula (2) are based on linear or branchedsiloxanes, one or more siloxane radicals being able to occur permolecule.

The preparation of compounds of the general formulae (1) and (2) takesplace preferably by hydrosilylation. Si—H-functional cyclosiloxanes andbranched or linear siloxanes can thus be linked to C—C unsaturatedorganic structures (B. Marciniec: Comprehensive Handbook onHydrosilylation, Pergamon Press, 1992). Desired monomer structures ofthe general formulae can be represented in this way.

Preferred Si—H-functional silicon core pieces for conversion torepresentatives of formulae (1) and (2) according to the invention areexemplary and include without limitation: D^(H) ₄, D^(H) ₅, D^(H) ₇,D^(H) ₈, a mixture of D^(H) _(x), with x=4, 5, 6, 7, 8, 9, 10 (sum ofthese components >90%), M^(H) ₂, M^(H) ₄Q, M^(H) ₃T, M^(H) ₃T^(H), M^(H)₃T^(Ph), M^(H) ₈Q₈, T^(H) ₈ (silicon nomenclature according toEncyclopedia of Polymer Science and Engineering 2^(nd) Ed. Vol. 15 p.206ff; H=hydrido-functionalized, Ph=phenyl).

For example, 1,3,5,7-tetramethylcyclotetrasiloxane in a solvent such astoluene, under the influence of precious-metal catalysts such as(without limitation thereto) Speier catalysts, Karstedt catalysts butalso Wilkinson catalysts, can be linked to four mol vinylbenzylmethacrylate to a representative of (1). Instead of thecyclotetrasiloxane, a commercially available mixture of SiH-cycles(Petrarch, M8830) (a mixture of D^(H) _(x), with x=4, 5, 6) can also beused. Instead of vinylbenzyl methacrylate, other unsaturated compoundssuch as vinylnorbornenol methacrylate or allyl ethers, esters or amidesof (meth)acrylate-functional Bisphenol-A derivatives, as well asendocyclic unsaturated and other (meth)acryl-functional organicmolecules can be used. A further possibility according to the inventionis to react the cyclosiloxane component not only with aromatic orpolycyclic hydrosilylatable (meth)acrylates, but to do this in themixture with aliphatic hydrosilylatable (meth)acrylates such as forexample allyloxyethyl methacrylate or glycerol dimethacrylate allylether. However, products according to the invention are only theportions which carry at least one aromatic or polycyclic (meth)acrylatecomponent in the molecule.

In the case of the reaction of polyfunctional SiH-cyclosiloxanes withlikewise multiple C—C unsaturated organic structures (with the exceptionof the polymerizable double bonds), all C—C unsaturated functions of theorganic structure can be saturated with in each case a cyclosiloxanering through a suitable reaction procedure. However, pre-cross-linkedintermediate products can also be produced by a different choice ofstoichiometry or reaction procedure.

Both possibilities can be used independently of each other.

The structures shown in the following can be obtained in per se knownmanner by hydrosilylation of suitable Si—H compounds, for example withallyl or vinyl compounds. In the case of hydrosilylation, a mixture ofisomeric adducts are obtained in various proportions (α- and β-adduct:see schema (I)) independently of the substrates and the catalyst. Ineach case, only one isomer is shown in the formulae, but allpossibilities are meant.

In addition to the methacrylates shown in the preferred examples, thecorresponding acrylates as well as mixed types are also preferred.

Preferred representatives of formula (1) are:

m=4, 5 or a mixture of 4, 5 and 6 (i.e.: n=0, 1, 2); x=1 to m−1,Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; X=1,2-ethylene,T=1-oxa-1,3-propylene, L=methacrylate.

m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2);Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate.

m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2);Q=1,2-ethylene-(2-(4-methyleneoxyl-1,4(3)-phenylene); L=methacrylate.

m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl; D=E;G=1,4-butylene, a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl;L=methacrylate.

m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl; D=E;G=1,2-ethylene, a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl;L=methacrylate.

m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl; D=E;G=4,7-dioxa-8-oxo-1,10-decylene, a=2; Q=1,4-phenylene;T=1,2-ethanediol-diyl; L=methacrylate.

m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl; D=E;G=4-oxa-1,4-butylene-4-(1,4-phenylene); a=2; Q=1,4-phenylene;T=1,2-ethanediol-diyl; L=methacrylate.

m=4 (with n=0); A=methyl; D=E,bis-[2,2-propanediyl-(4-(1,3-propylene-oxy)-1-phenylene);Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate.

m=4 (with n=0); A=methyl; D=E, bis-[1,4-(1,2-ethanediyl)-phenylene);Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate.

m=4, 5 or a mixture of 4, 5 and 6 (with n=0, 1, 2); A=methyl; D=E;Q=2(3)-oxyl-tricyclo[5.2.1.0^(2,6)]decane-6(7)-yl; L=methacrylate.

Preferred representatives of formula (2) are:

x=2; y=0; z=0; K=methyl, G-C[(Q-T-L)_(a)A_(3-a)]; G=1,4-butylene;A=methyl; a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl; L=methacrylate.

x=2; y=0; z=0; K=methyl, G-C[(Q-T-L)_(a)A_(3a)]; G=1,2-ethylene;A=methyl; a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl; L=methacrylate.

x=2; y=0; z=0; K=methyl,G-C[(Q-T-L)_(a)A_(3-a]; G=)4,7-dioxa-8-oxo-1,10-decylene; A=methyl; a=2;Q=1,4-phenylene; T=1,2-ethanediol-diyl; L=methacrylate.

x=2; y=0; z=0; K=methyl,G-C[(Q-T-L)_(a)A_(3-a]; G=)4-oxa-1,4-butylene-4-(1,4-phenylene;A=methyl; a=2; Q=1,4-phenylene; T=1,2-ethanediol-diyl; L=methacrylate.

x=4; y=0; z=1; K=methyl, Q-L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate.

x=3; y=1; z=0; K=methyl, Q-L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate.

x=3; y=1; z=0; K=methyl, Q-L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate.

x=3; y=1; z=0; K=methyl, phenyl, Q-L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-1,2-(ethanediyl)-yl; L=methacrylate.

x=4; y=0; z=1; K=methyl, Q-L;Q=1,2-ethylene-(2-(4-methyleneoxyl-1,4(3)-phenylene); L=methacrylate.

x=4; y=0; z=1; K=methyl, 1,4-phenylene, Q-L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate.

x=2; y=0; z=0; K=methyl, Q-L;Q=2(3)-oxyl-bicyclo[2.2.1]hept-5-(1,2-ethanediyl)-yl; L=methacrylate.

x=2; y=0; z=0; K=methyl, Q-L;Q=1,2-ethylene-(2-(4-methyleneoxyl-1,4(3)-phenylene); L=methacrylate.

According to the invention, there can also be prepared from the monomersaccording to formulae (1) and/or (2) curable materials containing:

-   (K1) 0 to 70, preferably 0 to 20 wt.-% monomers according to formula    (1),-   (K2) 0 to 70, preferably 0 to 20 wt.-% monomers according to formula    (2),-   (K3) 0 to 50, preferably 3 to 20 wt.-% co-monomers,-   (K4) 20 to 90, preferably 70 to 85 wt.-% fillers,-   (K5) 0.001 to 5, preferably 0.1 to 2 wt.-% initiators,-   (K6) 0 to 20, preferably 0 to 5 wt.-% auxiliaries,    with the proviso that the sum of the components (K1) and (K2) is at    least 10 wt.-%, preferably at least 12 wt.-%.

Co-monomers according to component (K3) are at least singlyethylenically unsaturated. Preferably used ethylenically unsaturatedco-monomers are acrylates or methacrylates. Mono- and polyfunctional(meth)acrylate monomers are generally suitable. Typical representativesof this class of compounds (DE-A-43 28 960) are alkyl(meth)acrylates,including the cycloalkyl(meth)acrylates, aralkyl(meth)acrylates and2-hydroxyalkyl (meth)acrylates, for example hydroxypropyl methacrylate,hydroxyethyl methacrylate, isobornyl acrylate, isobornyl methacrylate,butyl glycol methacrylate, acetyl glycol methacrylate, triethyleneglycol dimethacrylate, polyethylene glycol dimethacrylate,2-phenyl-ethyl methacrylate, 2-ethylhexyl methacrylate, cyclohexylmethacrylate, lauryl methacrylate and hexanediol di(meth)acrylate.Long-chained monomers based on Bisphenol A and glycidyl methacrylate,which are known from U.S. Pat. No. 3,066,112, or their derivativesresulting from addition of isocyanates can also be used. Compounds ofthe Bisphenyl-A-diethyloxy(meth)acrylate andBisphenol-A-dipropyloxy(meth)acrylate type are also suitable. Theoligoethoxylated and oligopropoxylated Bisphenol-A diacrylic anddimethacrylic acid esters can also be used. The diacrylic anddimethacrylic acid esters ofbis(hydroxymethyl)-tricyclo[5.2.1.0^(2,6)]-decane named in DE-C-28 16823 and the diacrylic and dimethacrylic acid esters of the compounds ofbis(hydroxymethyl)-tricyclo[5.2.1.0^(2,6)]-decane extended with 1 to 3ethylene oxide and/or propylene oxide units are also well suited.

Inorganic fillers can as a rule be used as fillers according tocomponent (K4). Quartz, ground glasses, silica gels as well as pyrogenicsilicic acids and precipitation silicic acids or their granules can becited as examples. X-ray-opaque fillers are also preferably used, atleast partially. These can for example be X-ray-opaque glasses, i.e.glasses which for example contain strontium, barium or lanthanum (e.g.according to U.S. Pat. No. 3,971,754) or some of the fillers consist ofan X-ray-opaque additive, such as for example yttrium trifluoride,strontium hexafluorozirconate or fluorides of the rare earth metals(e.g. according to EP-A-0 238 025). For better incorporation into thepolymer matrix, it is advantageous to hydrophobize the inorganicfillers. Customary hydrophobization agents are silanes, for exampletrimethoxymethacryloyloxypropyl silane or trimethoxyglycidyl silane.

The fillers preferably have an average grain size <20 μm, in particular<5 μm and an upper grain limit of 150 μm, preferably 70 μm and inparticular 25 μm.

Mixtures of 5 to 25 wt.-% fillers with an average grain size of 0.02 to0.06 μm and 65 to 85 wt.-% fillers with an average grain size of 1 to 5μm are particularly preferably used.

Such systems which in a suitable period of time are able to formradicals are used as initiators according to component (K5). In the caseof single-component materials, photoinitiators which can trigger thepolymerization reaction through irradiation with UV or visible light areused for this.

Representatives of such photoinitiators are for example benzoin alkylethers, benzil ketals, acylphosphinic oxides or aliphatic and aromatic1,2-diketone compounds, for example camphorquinone, the lightpolymerization being able to be accelerated by the addition ofactivators, such as tertiary amines or organic phosphites, in a mannerknown per se.

Suitable initiator systems for the triggering of the polymerization viaa redox mechanism are for example the peroxide/amine orperoxide/barbituric acid derivatives systems or similar. When using suchinitiator systems, it is expedient to keep an initiator (e.g. peroxide)and a catalyst component (e.g. amine) ready separately. The twocomponents are then homogeneously mixed with each other shortly beforethey are used.

Suitable auxiliaries according to component (K6) can for examplenormally be stabilizers, pigments or thinning agents used in the fieldof dentistry.

The preparation process of the materials disclosed here is preferablysuch that the liquid constituents are mixed with one another, theinitiators, if they are not liquid, are introduced therein by stirringand the fillers are then added. A good homogenization can be achieved bykneading.

Two-component preparations which are cured by redox mechanisms areformulated such that the essential constituents of the redox initiationsystem are each introduced separately into a part of the two-componentpreparation. The distribution of the constituents of the overallpreparation is based on the relevant storage properties and the desiredmixing ratio.

The polymerizable materials are characterized by a highfilling-substance content and associated high strength withsimultaneously good processability.

The materials according to the invention are suitable in particular asmaterials for dental purposes, for example for the production ofartificial teeth or temporary fittings, as coating products, for thegluing of substrates and as dental filling materials.

The materials according to the invention are usually introduced intoreceptacles such as tubular bags, single- or multi-chambered cartridgesor capsules and other application units, for example blister packs orsyringes, as known from the field of dentistry.

The invention is described in more detail in the following by exampleswithout being limited thereby.

EXAMPLES Preparation Example 1 Preparation of1,3,5,7-tetrakis[2(3)-methacryloyl-bicyclo[2.2.1]heptane-5-(1,3-propanediyl]-1,3,5,7-tetramethyl-cyclotetrasiloxane(1.1)

10 g (41.6 mmol) 1,3,5,7-tetramethylcyclotetrasiloxane are dissolved in50 ml of toluene and stirred with 34.3 g (166 mmol)5-vinyl-2(3)-norbornanyl-methacrylate (prepared according to U.S. Pat.No. 3,927,116) and with Karstedt catalyst (3 to 3.5% Pt, 200 ppm Pt,ABCR) for 24 hours. The reaction is checked by means of IR and, if anySi—H bands are still present at approximately 2100 cm⁻¹, subsequentlystirred until the bands disappear. After the customary working up andproduct isolation, 45.2 g (93%) of a bright-yellow viscous oil areobtained. Viscosity η (23° C.)=70 Pa*s, n_(D) ²⁰=1.496.

Preparation Example 2 Preparation of1,3,5,7-tetrakis[4(3)-methacryloylmethylene-phenyl-1-(1,2-ethanediyl]-1,3,5,7-tetramethyl-cyclotetrasiloxane(1.3)

10 g (41.6 mmol) of 1,3,5,7-tetramethylcyclotetrasiloxane are dissolvedin 50 ml toluene and stirred with 33.7 g (166 mmol)4(3)-vinylbenzyl-methacrylate (prepared according to Example 1 of EP-A-0381 005) and with Karstedt catalyst (3 to 3.5% Pt, 200 ppm Pt, ABCR) for24 hours. The reaction is checked by means of IR and, if any Si—H bandsare still present at approximately 2100 cm⁻¹, subsequently stirred untilthe bands disappear. After the customary working up and productisolation, 45.2 g (93%) of a bright-yellow viscous oil are obtained.Viscosity η (23° C.)=45 Pa*s, n_(D) ²⁰=1.528.

Preparation Example 3 Preparation of1,5-bis[2(3)-methacryloyl-bicyclo[2.2.1]heptane-5-(1,2-ethanediyl]-1,1,5,5-tetramethyl-3,3-bis-[2-(2(3)-methacryloyl-bicyclo[2.2.1]heptane-5-(1,2-ethanediyl)-2,2-dimethylsiloxy]-trisiloxane(2.5)

10 g (30.4 mmol) tetrakis-dimethylsiloxy-silane are dissolved in 50 mltoluene and stirred with 25.1 g (122 mmol)5-vinyl-2(3)-norbornanyl-methacrylate (prepared according to Example XIVof U.S. Pat. No. 3,927,116) and with Karstedt catalyst (3 to 3.5% Pt,200 ppm Pt, ABCR) for 24 hours. The reaction is checked by means of IRand, if any Si—H bands are still present at approximately 2100 cm⁻¹,subsequently stirred until the bands disappear. After the customaryworking up and product isolation, 45.2 g (93%) of a bright-yellowviscous oil are obtained. Viscosity η (23° C.)=12 Pa*s, n_(D) ²⁰=1.492.

Preparation Example 4 Preparation of1,4-bis[2-(1,3,5,7-tetramethyl-1,3,5,7-(2(3)-methacryloyl-bicyclo[2.2.1]heptane-5-(1,2-ethanediyl)-cyclotetrasiloxanyl)-1,2-ethanediyl]-benzene(1.8)

625 g (2.6 mol) 1,3,5,7-tetramethyl-cyclotetrasiloxane are introducedunder reflux with 500 ml toluene and 0.8 g platinum on active carbon.169 g divinylbenzene (1.3 mol; 80%, technical, Aldrich) are added tothis. After the disappearance of the vinylic protons in the ¹H-NMR,processing is carried out in the usual way. 587 g (92% of thetheoretical value) of a colourless oil with the viscosity η (23° C.)=0.3Pa*s and a refractive index of 1.471 are obtained.

21.7 g (0.105 mol) 5-vinyl-2(3)-norbornanyl-methacrylate and 50 mltoluene are reacted with Karstedt catalyst (3 to 3.5% Pt, 200 ppm Pt,ABCR). 11.3 g of the oil prepared in the previous paragraph are addeddropwise at 50° C. and the mixture stirred for 24 hours. The reaction ischecked by means of IR and, if any Si—H bands are still present atapproximately 2100 cm⁻¹, stirred until the bands disappear. After thecustomary working up and product isolation, 29.0 g (88%) of abright-yellow viscous oil are obtained. Viscosity η (23° C.)=78 Pa*s,n_(D) ²⁰=1.480.

Preparation Example 5 Reaction of a Mixture of SiH-Cycles with a Mixtureof Allyloxyethyl Methacrylate and 5-vinyl-2(3)-norbornanyl-methacrylate

10 g (166 mmol based on SiH) of a mixture of SiH-cycles (40% D^(H) ₄,45% D^(H) ₅, the rest higher rings) are dissolved in 50 ml toluene andstirred with a mixture of 17.2 g (84 mmol)5-vinyl-2(3)-norbornanyl-methacrylate (prepared according to U.S. Pat.No. 3,927,116), 14.3 g (84 mmol) allyloxyethyl methacrylate andhexachloroplatinic acid (dissolved in i-propanol) for 24 hours. Thereaction is checked by means of IR and, if any Si—H bands are stillpresent at approximately 2100 cm⁻¹, subsequently stirred until the bandsdisappear. After the customary working up and product isolation, 40 g(96%) of a bright-yellow viscous oil are obtained. Viscosity 2 Pa*s,n_(D) ²⁰=1.486.

Application Examples, Comparison Example

The pasty preparations according to the application examples and thecomparison example, the compositions of which are described in Table 1,were prepared in a 100-ml laboratory kneader.

The preparations were characterized in accordance with DIN ISO 4049 inrespect of compression and bending strength.

The testpieces were prepared by irradiation of the materials introducedinto moulds over a period of 40 seconds using the Elipar® II lightingdevice of ESPE Dental AG, Germany.

Following removal from the mould, the testpieces were stored indeionized water at 36° C. for a period of 24 hours, after which themechanical properties were ascertained.

The volume shrinkage occurring during the radical polymerization wasestablished by measuring the densities of the pasty preparations and ofthe cured compositions, using the Archimedes buoyancy method.

The opacity was measured by means of specimens with a defined height of3.5 (+/−0.05) mm. These are prepared by filling the material to bechecked into suitably high rings, evenly and free of bubbles, andilluminating it in the contact every 40 s by means of a lighting device(Elipar® II, ESPE) between plane, transparent matrices. The demouldedspecimens are then subsequently hardened under vacuum in a lightingdevice (Visio® beta, ESPE) for another 15 mins. The opacity is thenmeasured with the colour measuring device “HunterLab LabScanSpectralcolorimeter” of Hunter Lab Associates Laboratory, Inc., USA(Software SpecWare Software Version 1.10) and given by the device in%-values.

A summary of the property values ascertained for the cured preparationsaccording to the application examples or the comparison example is shownin Table 2.

TABLE 1 Composition of the pasty preparations according to theapplication examples or the comparison example. Application ComparisonConstituent example No. example No. (Proportions in wt.-%) A1 A2 A3 V1V2 V3 (K1) Monomer according to preferred representative 1.1 22.5 10.311.3 (K1) Monomer according to preferred representative 1.8 10.3 (K1)Monomer according to preferred representative 2.5 11.31,3,5,7-tetramethyl-1,3,5,7-tetrakis-(3-methacryloxypropyl)- 9.6 22.4cyclotetrasiloxane2,2-bis-4(3-hydroxypropoxyphenyl)propane-dimethacrylate 7.67,7,9-trimethyl-4, 13-dioxo-3, 14-dioxa-5, 12-diaza-hexadecane- 11.81,16-dioldimethacrylate Bis-acryloylmethyltricyclo[5.2.1.0^(2,6)]decane15.7 (K2) Sr silicate glass, average particle size 1.2 micrometers, 73.976.4 74.0 35.0 77.1 silanized (K2) Pyrogenic silicic acid 3.1 2.5 2.9(K2) Quartz powder, average particle size 1.5 micrometers, 41.2 78.1silanized (K5) 2,2′-(3-methoxypropylnitrilo)diethanoldimethacrylate 0.40.4 0.4 0.4 0.4 0.4 (K5) 1,7,7-trimethyl-bicyclo[2.2.1]heptane-2,3-dion0.07 0.07 0.07 0.06 0.07 0.07

TABLE 2 Composition of the property values, ascertained for the curedpreparations according to the application examples or the comparisonexample. Application example Comparison No. example No. Property A1 A2A3 V1 V2 V3 Compression strength [MPa] 380 373 405 411 416 345 Bendingstrength [MPa] 109 99 115 117 97 92 Elasticity modulus [MPa] 9678 895210025 8120 7348 4569 Volume shrinkage [%] 1.70 2.35 2.32 3.67 2.81 2.67Opacity in [%] 84 80 80 82 96 98

The dental materials prepared using the monomers according to theinvention show an opacity of approximately 85%, which makes possible thevisual impression of natural tooth substance. The comparison examplesare either clearly more opaque, as a result of which the restorationmaterial has an unsatisfactory aesthetic appearance, or containlow-molecular monomers and therefore do not meet the toxicologicalrequirements.

Outstanding physical values with optimal opacity can be achieved withthe dental materials prepared from the high-molecular monomers accordingto the invention.

In particular the volume shrinkage is extremely low and the dentalmaterials are therefore well suited for the permanent restorative careof a patient.

1. Monomers according to the following formula:

in which the following mean: n=an integer from 0 to 10; A=H or linear orbranched C₁ to C₁₅ alk(en) yl, or C₃ to C₁₅ cycloalk(en)yl or C₆ to C₁₂aryl or C₈-C₁₈ alkaryl, of the named radicals, one or more C atoms ineach case being able to be replaced by O, C═O, O(C═O), and/or NR, Rbeing an aliphatic radical with 1 to 7 C atoms, in which one or more Catoms can be replaced by O, C═O and/or O(C═O); D=E or a hydrocarbonstructure which links 2 to 10 cyclosiloxane radicals, the structurebeing linear or branched or cyclic or polycyclic and containing 2 to 50C atoms and additionally 0 to 30 other atoms from the group O, N, S, F,Cl, F, Br, I and to which 1 to 9 of the above-defined cyclosiloxaneradicals according to formula (1), excluding D, are attached; E=A or apolymerizable group taken from the group G-C[(Q-T-L)_(a)(A)_(3-a)]and/or Q-L and optionally also X-T-L, up to 50% of groups E beingpermitted to correspond to A in an average molecule, with the provisothat in the case of molecules with only one siloxane ring, under 25% to0% of the groups E are permitted to correspond to A in an averagemolecule, and with the proviso that at least one groupG-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L must be contained in the molecule;G=linear, branched or cyclic C₁ to C₂₅ alk(en)ylene, arylene,alkarylene, arylalkylene, 0 to 5 C atoms being able to be replaced by arepresentative of the group O, S, N-A, C(O), C(O)O, OC(O), C(O)N, NC(O),OC(O)O, NC(O)O, OC(O)N, NC(O)N; X=C₁ to C₁₀ alk(en)ylene; Q=a radicalcontaining an aromatic or polycyclic ring system in the chain, with 5 to20 C atoms, which independently of each other also has 0 to 5heteroatoms from the group O, N-A, S in the ring system, with theexception of tricyclo[5.2.1.0^(2.6)]decanyl-groups; T=O, N-A or a bi- ormultivalent linear, branched or cyclic alcohol, amine or amino alcoholradical with 2 to 10 C atoms; L=an acrylate or methacrylate group; a=2,3.
 2. Monomers according to the following formula:

in which the following mean: x≦2+y+2z; y=0, 1, 2, 3, 4, 5, 6, 7, 8; z=0,1, 2, 3, 4, 5, 6, 7, 8; A=hydrogen or linear or branched C₁ to C₁₅alk(en)yl, or C₃ to C₁₅ cycloalk(en)yl or C₆ to C₁₂ aryl or C₈-C₁₈alkaryl, of the named radicals, one or more C atoms in each case beingable to be replaced by O, C═O, O(C═O), and/or NR, R being an aliphaticradical with 1 to 7 C atoms, in which one or more C atoms can bereplaced by O, C═O and/or C(C═O); D=E or a hydrocarbon structure whichlinks 2 to 10 cyclosiloxane radicals, the structure being linear orbranched or cyclic or polycyclic and containing 2 to 50 C atoms andadditionally 0 to 30 other atoms from the group O, N, S, P, Cl, F, Br, Iand to which 1 to 9 of the above-defined cyclosiloxane radicalsaccording to formula (1), excluding D, are attached; E=A or apolymerizable group taken from the group G-C[(Q-T-L)_(a)(A)_(3-a)]and/or Q-L and optionally also X-T-L, up to 50% of groups E beingpermitted to correspond to A in an average molecule, with the provisothat in the case of molecules with only one siloxane ring, under 25% to0% of the groups E are permitted to correspond to A in an averagemolecule, and with the proviso that at least one groupG-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L must be contained in the molecule;Q=a radical containing an aromatic or polycyclic ring system in thechain, with 5 to 20 C atoms, which independently of each other also has0 to 5 heteroatoms from the group O, N-A, S in the ring system, with theexception of tricyclo[5.2.1.0^(2.6)]decanyl-groups; and L=an acrylate ormethacrylate group with the proviso that at least three of the radicalsD in a molecule must have the meaning of G-C[(Q-T-L)_(a)(A)_(3-a)] orQ-L or X-T-L, and with the proviso that where y=z=0, at least oneradical D has the meaning of G-C[(Q-T-L)_(a)(A)_(3-a)].
 3. Compositionscontaining (a) 0 to 70 monomers according to the following formula:

in which the following mean: n=an integer from 0 to 10; A=H or linear orbranched C₁ to C₁₅ alk(en)yl, or C₃ to C₁₅ cycloalk(en)yl or C₆ to C₁₂aryl or C₈-C₁₈ alkaryl, of the named radicals, one or more C atoms ineach case being able to be replaced by O, C═O, O(C═O), and/or NR, Rbeing an aliphatic radical with 1 to 7 C atoms, in which one or more Catoms can be replaced by O, C═O and/or O(C═O); D=E or a hydrocarbonstructure which links 2 to 10 cyclosiloxane radicals, the structurebeing linear or branched or cyclic or polycyclic and containing 2 to 50C atoms and additionally 0 to 30 other atoms from the group O, N, S, P,Cl, F, Br, I and to which 1 to 9 of the above-defined cyclosiloxaneradicals according to formula (1), excluding D, are attached; E=A or apolymerizable group taken from the group G-C[(Q-T-L)_(a)(A)_(3-a)]and/or Q-L and optionally also X-T-L, up to 50% of groups E beingpermitted to correspond to A in an average molecule, with the provisothat in the case of molecules with only one siloxane ring, under 25% to0% of the groups E are permitted to correspond to A in an averagemolecule, and with the proviso that at least one groupG-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L must be contained in the molecule;G=linear, branched or cyclic C₁ to C₂₅ alk(en)ylene, arylene,alkarylene, arylalkylene, 0 to 5 C atoms being able to be replaced by arepresentative of the group O, S, N-A, C(O), C(O)O, OC(O), C(O)N, NC(O),OC(O)O, NC(O)O, OC(O)N, NC(O)N; X=C₁ to C₁₀ alk(en)ylene; Q=a radicalcontaining an aromatic or polycyclic ring system in the chain, with 5 to20 C atoms, which independently of each other also has 0 to 5heteroatoms from the group O, N-A, S in the ring system, with theexception of tricyclo[5.2.1.0^(2.6)]decanyl-groups; T=O, N-A or a bi- ormultivalent linear, branched or cyclic alcohol, amine or amino alcoholradical with 2 to 10 C atoms; L=an acrylate or methacrylate group; a=2,3, (b) 0 to 70 monomers according to the following formula:

in which the following mean: x≦2+y+2z; y=0, 1, 2, 3, 4, 5, 6, 7, 8; z=0,1, 2, 3, 4, 5, 6, 7, 8; A=hydrogen or linear or branched C₁ to C₁₅alk(en)yl, or C₃ to C₁₅ cycloalk(en)yl or C₆ to C₁₂ aryl or C₈-C₁₈alkaryl, of the named radicals, one or more C atoms in each case beingable to be replaced by O, C═O, O(C═O), and/or NR, R being an aliphaticradical with 1 to 7 C atoms, in which one or more C atoms can bereplaced by O, C═O and/or O(C═O); D=E or a hydrocarbon structure whichlinks 2 to 10 cyclosiloxane radicals, the structure being linear orbranched or cyclic or polycyclic and containing 2 to 50 C atoms andadditionally 0 to 30 other atoms from the group O, N, S, P, Cl, F, Br, Iand to which 1 to 9 of the above-defined cyclosiloxane radicalsaccording to formula (1), excluding D, are attached; E=A or apolymerizable group taken from the group G-C[(Q-T-L)_(a)(A)_(3-a)]and/or Q-L and optionally also X-T-L, up to 50% of groups E beingpermitted to correspond to A in an average molecule, with the provisothat in the case of molecules with only one siloxane ring, under 25% to0% of the groups E are permitted to correspond to A in an averagemolecule, and with the proviso that at least one groupG-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L must be contained in the molecule;Q=a radical containing an aromatic or polycyclic ring system in thechain, with 5 to 20 C atoms, which independently of each other also has0 to 5 heteroatoms from the group O, N-A, S in the ring system, with theexception of tricyclo[5.2.1.0^(2.6)]decanyl-groups; and L=an acrylate ormethacrylate group with the proviso that at least three of the radicalsD in a molecule must have the meaning of G-C[(Q-T-L)_(a)(A)_(3-a)] orQ-L or X-T-L, and with the proviso that where y=z=0, at least oneradical D has the meaning of G-C[(Q-T-L)_(a)(A)_(3-a)], (c) 0 to 50co-monomers, (d) 20 to 90 wt.-% fillers, (e) 0.001 to 5 wt.-%initiators, and (f) 0 to 20 auxiliaries, with the proviso that the sumof the components (a) and (b) is at least 10 wt.-%.
 4. Compositionsaccording to claim 3 with an opacity of 80 to 90%.
 5. A method for thepreparation of a dental material comprising curing monomers according toclaim 1 to produce a dental material having an opacity which provides avisual impression of a natural tooth substance.
 6. A receptaclecontaining at least one material including monomers according to any oneof claims 1 and
 2. 7. A receptacle containing at least one compositionaccording to any one of claims 3 and
 4. 8. A method for the preparationof a curable material comprising curing cyclic siloxanes containing atleast one side chain G-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L according toclaim 1 or linear siloxanes containing at least one side chainG-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L according to claim 2 to produce acurable material having an opacity of 80 to 90%.
 9. A method for thepreparation of a dental material comprising curing monomers according toclaim 2 to produce a dental material having an opacity which provides avisual impression of a natural tooth substance.
 10. A method for thepreparation of a dental material comprising curing compositionsaccording to claim 3 to produce a dental material having an opacitywhich provides a visual impression of a natural tooth substance.
 11. Amethod for the preparation of a dental material comprising curingcompositions according to claim 4 to produce a dental material having anopacity which provides a visual impression of a natural tooth substance.12. Monomers according to claim 1 or 2 wherein: D=E or a hydrocarbonstructure which links 2 to 5 cyclosiloxane radicals, the structure beinglinear or branched or cyclic or polycyclic and containing 2 to 50 Catoms and additionally 0 to 30 other atoms from the group O, N, S, P,Cl, F, Br, I and to which 1 to 9 of the above-defined cyclosiloxaneradicals according to formula (1), excluding D, are attached. 13.Monomers according to claim 1 wherein: E=A or a polymerizable grouptaken from the group G-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L and optionallyalso X-T-L, 25% to 0% of groups E being permitted to correspond to A inan average molecule, with the proviso that in the case of molecules withonly one siloxane ring, under 25% to 0% of the groups E are permitted tocorrespond to A in an average molecule, and with the proviso that atleast one group G-C[(Q-T-L)_(a)(A)_(3-a)] and/or Q-L must be containedin the molecule.